We are attempting to carry out a practical synthesis of the prostaglandins PGE1 and PGE2 starting from readily available materials. These syntheses utilize a new tactic for the construction of substituted 1,4-keto-aldehydes which in turn are cyclized into their corresponding 4-hydroxy-cyclopentenone analogues. This synthetic strategy differs considerably from previously reported approaches hydroxy-cyclo-pentenone systems and holds promise of being both technically simple as well as highly efficient. The synthetic scheme is designed to allow a wide number of structural variations to be introduced into the basic prostaglandin skeleton. In addition, it permits isotopic labeling of the prostaglandin molecule at a number of positions, an advantage which should be of value in biochemical and pharmacological studies.